1. Field of the Invention
The present invention relates to a wiring substrate, a manufacturing method thereof using a droplet discharge method, a semiconductor device, and a manufacturing method thereof. Note that the semiconductor device of the present specification indicates devices in general that may perform by utilizing semiconductor properties. For example, a display device, an electro-optical device, a semiconductor circuit, and an electronic appliance are all semiconductor devices.
2. Description of the Related Art
In recent years, a droplet discharge method is applied to the field of a flat-panel display, and the development proceeds actively. The droplet discharge method has many advantages: for example, a mask is not required since a droplet can be directly applied, the method is easy to be applied to a large-scale substrate, and the material has high usability. Therefore, the droplet discharge method is applied to manufacturing a color filter, and an electrode of a plasma display, and the like.
In order to form a wiring to be thin, discharge amount is controlled and a base surface is treated in plasma, for example, during forming a pattern such as a wiring of an electric appliance by a droplet discharge method. (For example, refer to Patent Document 1: Japanese Patent Laid-Open No. 2003-133691.) Accordingly, forming the wiring of approximately 50 μm is possible.
In the field of electric appliances, it is expected to form a wiring having thinner width. For example, a technique to form a wiring having a width of about from 5 to 10 μm is required for a display panel.
However, a wiring cannot be sufficiently thinned by only the surface treatment of base surface that is performed in the conventional art. Moreover, by using the plasma treatment, the condition of the surface is modified temporarily, but the condition changes as time goes by. Therefore, there is a problem of repeatability in process.